Review: BMC Fourstroke 02 XT

 

Our test model is the BMC Fourstroke 02 which features a full carbon front triangle and aluminum rear triangle. Full carbon is available at the top of the Fourstroke range with the 01. Underpinning the Fourstroke platform are two concepts from BMC: first is their Advanced Pivot System (APS) - a suspension design which aims to optimise pedalling efficiency while still soaking up bumps; the second is their Big Wheel Concept (BWC) - simply put, it’s an approach to geometry said to improve the stability and agility of a 29 inch bike through subtle, purposeful tweaks.

 

The frame carries the signature BMC look of oversized angular tubing and smooth junctions. Cables run externally below the down tube keeping the top half of the frame uncluttered and keeping maintenance easy. The head tube across the size curve is significantly shorter than most in this class (110mm on the Large), allowing riders to get the bars super low without the need for negative drop stems. BMC also pay attention to the chainstay length, keeping these short (445mm) and the bottom bracket low (40mm drop) to improve traction and stability.

 

The Build

The BMC Fourstroke 02 as tested is built up with a solid component specification. It features Shimano XT throughout with a 2x11 drivetrain. A Fox Float 32 Performance fork and Fox Float DPS EVOL shock provide 100mm travel front and rear, both featuring remote lockout levers. For my tastes and preference, the remote lockouts are an unnecessary addition, only adding clutter to the cockpit.

 

The build is rounded off with a set of DT Swiss X1700 Spline Two wheels with a Continental X-King on the front and Race King (2.2) on the rear (our test model featured Onza Canis front and rear). The finishing kit comprises of BMC’s house brand alloy stem, handlebar (720mm), and seatpost paired with a Fizik Tundra M7 saddle.

 

The model, as tested, is the 2016 specification with the 2017 lineup offering a very similar spec with some subtle updates: notably a mix of Shimano XT and the new SLX and the new Fox Float SC fork. See the full specification here.

 

• FrameFourstroke 02 - Advanced Pivot System
• ForkFox 32 Float Performance Series FIT4 Remote (100mm)
• ShockFox Float EVOL Performance Series DPS Remote (100mm)
• CranksetShimano XT, 36-26T
• Rear DerailleurShimano XT Shadow Plus
• ShiftersShimano XT
• CasetteShimano XT, 11-40T
• ChainShimano XT
• BrakesShimano XT (160/160mm)
• SeatpostBMC MSP 02, 31.6mm
• SaddleFizik Tundra M7
• StemBMC MSM 02
• HandlebarBMC MFB 02 720mm
• WheelsetDT Swiss X1700 Spline Two
• TyresContinental: X-King [F] / RaceKing [R], 2.2
• PriceRRP R 65,999.00 (Available from R55k at the time of publishing)

 

On the trail

Curious to see how the Advanced Pivot System (APS) works in the wild, my first port of call was to see just how well the Fourstroke pedals. The suspension is designed to counteract the inertial force generated when you accelerate which would ordinarily compress the shock creating inefficiency. This system combined with a stiff frame and one-piece rear triangle create an overwhelmingly sturdy ride with no noticeable flex in the frame nor any significant pedal bob under acceleration. Thanks to these qualities, despite a little extra weight in the rear, the Fourstroke 02 thrives on climbs and punchy accelerations.

 

When it comes to handling, the Fourstroke surprised me. Expecting a highly strung and skittish racer, the subtle geometry tweaks, which BMC dub their “Big Wheel Concept (BWC)”, make for a surprisingly comfortable and confident ride given the category. In corners, it’s impressively agile, yet not too twitchy or skittish. Only on very steep descents did I find the bike occasionally wanting to tip me over the bars as a result of the shorter headtube and low handlebar position. Here a dropper would help to get weight further back, behind the saddle (or a simple raise of the bar height). Overall, though, the shorter stem, wide bars and longer top tube (635mm on the Large tested) result in a secure riding position and sharp yet reliable handling.

 

On rougher terrain, the 100mm front and rear provide a healthy capability for typical South African trails. The sturdy frame and suspension design leave the shock and fork to do the hard work soaking up the bumps. Although the suspension tune and design appear to favour efficiency over comfort, the Fourstroke is confident and stable through bumpy terrain. Here the stiff and reliable DT Swiss X1700 wheelset help to keep things headed in the right direction.